Risk Assessment Of Geological Hazards In Hancheng Cities Based On Cluster Analysis

Hancheng City is located in the West Bank of the Yellow River in the east of Shaanxi Province and the northeast corner of Guanzhong Basin.Because it is located at the junction of structure,the stress is relatively concentrated and the rock is relatively broken.At the same time,Hancheng City is the main coal development base in Shaanxi Province.It has a long history of coal mining.When mining coal,it often produces goafs,which leads to various geological hazards.Landslides,collapses,and ground collapses are widely distributed in the study area,which seriously endangers the safety of people's lives and property and restricts the local economic development.Taking the geological hazards developed in Hancheng as the research object,the field survey and indoor analysis methods are used to summarize the development characteristics and distribution rules of geohazards in Hancheng.In virtue of ArcGIS and IBM SPSS Statistics 22,and using cluster analysis method,based on the theory of geological hazard risk assessment,the risk assessment of geological disasters in Hancheng City was conducted.The main conclusions are as follows:(1)There are 72 geological hazards in Hancheng,including 32 collapses(42.6%),16landslides(21.3%),and 24 ground collapses(32%).The geological hazards in Hancheng are mainly small and medium-sized,which account for 90.3%of the total.Human activities are the main inducing factors,58 of which are caused by human factors,accounting for 80.6%of the total.Among them,coal mining is the main inducing factor.There are 28 geological hazards caused by the production of mining enterprises,5 of which are caused by mining collapse and landslide,23 of which are caused by mining ground collapse.Spatially,it is mainly distributed in the low mountains and hills in the northeast and in loess terrace highland in the Southeast;spatially,it is mainly developed in July,August and September with more rainfall.(2)Through the data processing function of ArcGIS and the statistical analysis function of IBM SPSS statistics 22,the hazard and vulnerability zoning of Hancheng City were carried out respectively.The study is divided into high,medium,low and extremely low hazard areas by selecting 9 disaster causing factors and adopting K-means cluster analysis method,the areas with high risk are mainly distributed in low hills and loess source areas;the study is divided into high,medium,low and extremely low vulnerable areas by selecting5 disaster-bearing factors,taking each district and town as evaluation unit and adopting system cluster analysis method,areas with high vulnerability are mainly distributed in Jincheng District.(3)Through the grid calculator tool of ArcGIS,the Risk=Hazard×Vulnerability function is used to calculate the results of hazard and vulnerability zoning.The study area is divided into high,medium,low and extremely low risk areas,of which the area of high risk area is 32.68km~2,accounting for 2.06%of the total area,distributed in Jincheng district and Xincheng District;the area of medium risk area is 99.7km~2,accounting for 6.29%of the total area distributed in Jincheng District,Xincheng District and Longmen Town;the area of low risk area is 332.51km~2,accounting for 20.98%of the total area,distributed in Sangshuping Town,Longmen Town,Xizhuang Town,Banqiao Town and Zhichuan Town;the area of extremely low risk area is 1120.09km~2,accounting for 70.67%of the total area,distributed in most districts and towns in Hancheng.